Fix #15080 FP uninitMemberVarNoCtor for const and reference members

A class without constructor whose non-static const or reference member has
no default member initializer is not default constructible (or, for a const
class type with a default constructor, default constructs it), so the member
can never be left uninitialized.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: autoantwort

lib/checkclass.cpp

@@ -373,6 +373,10 @@ void CheckClassImpl::constructors()
                 if (var.typeScope() && var.typeScope()->numConstructors > 0)
                     continue;
 
+                // const and reference members without default initializer must be initialized by every instance
+                if (var.isConst() || var.isReference())
+                    continue;
+
                 if (diagVars.count(&var) == 0)
                     uninitVarError(var.nameToken(), false, FunctionType::eConstructor, var.scope()->className, var.name(), false, false, true);
             }

test/testconstructors.cpp

@@ -797,6 +797,23 @@ class TestConstructors : public TestFixture {
         ASSERT_EQUALS("[test.cpp:4:9]: (warning) Member variable 'T::j' has no initializer. [uninitMemberVarNoCtor]\n"
                       "[test.cpp:8:9]: (warning) Member variable 'U::k' has no initializer. [uninitMemberVarNoCtor]\n",
                       errout_str());
+
+        check("struct S {\n" // const and reference members can't stay uninitialized
+              "    int a = 0;\n"
+              "    const int b;\n"
+              "    int& c;\n"
+              "    const int* d;\n"
+              "};\n");
+        ASSERT_EQUALS("[test.cpp:5:16]: (warning) Member variable 'S::d' has no initializer. [uninitMemberVarNoCtor]\n", errout_str());
+
+        check("struct S {\n"
+              "    const std::array<std::uint8_t, 2> a;\n"
+              "    const std::vector<std::uint8_t>::const_iterator it;\n"
+              "};\n"
+              "S f(const std::vector<std::uint8_t>& v) {\n"
+              "    return S{ {}, v.cbegin() };\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
     }
 
     // ticket #4290 "False Positive: style (noConstructor): The class 'foo' does not have a constructor."